Some types of produce that are grown from seed, such as lettuce, typically are planted on raised beds with multiple seed lines or rows in each bed. The raised beds allow growers to irrigate crops with water through the furrows extending between adjacent beds. The multiple seed rows in each raised bed allow the growers to optimize crop yield per acre.
FIG. 1 shows a typical prior art three-row planting configuration with multiple raised beds 10 and a furrow 12 between each of the beds 10. Each bed has three lines or rows 14L, 14C, 14R, with the center row 14C being centered in the raised bed 10 and the left and right rows 14L and 14R being spaced nine inches from the center row 14C. Each bed typically has a 26 inch top width, while the furrows 12 are spaced approximately 40 inches center to center.
In the case of lettuce and other crops, it is common to over seed the seed lines 14L, 14C, 14R, and then later after the seeds have sprouted, come back through the field and manually thin each seed line to selectively kill unwanted plants, and thereby achieve a desired count or population per bed area. Preferably, the left and right outer lines 14L, 14R are staggered relative to the center line 14C, as shown in FIG. 2. For lettuce, the preferred spacing between each line 14L, 14C, and 14R is approximately nine inches on center, with preferred spacing of 11 inches between the desired plants or sprouted seeds in each row 14L, 14C, 14R, as shown in FIG. 3. This spacing and configuration optimizes the mature plant size, yield, and profit per acre. However, the manual thinning of undesired plants is expensive and wastes expensive seed. The spacing for other produce may be different than the spacing for lettuce.
More recently, precision planters with seed meters are utilized to minimize seed waste and reduce, but not eliminate, crop thinning to optimize the mature plant pattern. With precision planting, multiple seeds 16 are placed in each group 18 in each seed line 14L, 14C, 14R, so as to increase the likelihood of germination, compared to a group having only one or two seeds. The multi-seed group 18 is repeated at a desired distance (such as 11 inches on centers) to match the desired mature plant spacing. For example, each seed group 18 may include three seeds, as shown in FIGS. 4 and 5.
In practice, achieving the ideal stagger seed pattern in the field is not easy. The multi-seed group increases the likelihood of having a seed very near the ideal position, so that a skilled field worker can quickly visually identify and thin the appropriate unwanted plants.
This prior art precision planting practice almost always requires adjustment of the seed lines to achieve the desired pattern, which is not easy. Adjustment of the seed lines is typically achieved by jumping the drive chain on the seed meter sprocket, which is difficult to execute because the results of the adjustment are difficult to predict. Also, jumping the chain can only be made in finite, discreet amounts due to the sprocket teeth, with no ability for fine tuning the adjustment.
Another problem of precision planting is the inconsistent seed pattern from one field to the next field. This inconsistency arises due to seed depth adjustments to the row units, which affect the drive chain and sprocket geometry, and therefore affect seed placement and seed pattern for the bed.
Therefore, a primary objective of the present invention is the provision of a method and means for improved adjustability of a seed meter in a precision planting unit.
Another objective of the present invention is the provision of a precision planting unit that is more easily and more accurately adjustable.
A further objective of the present invention is the provision of an adjustment mechanism for precision planting unit seed meters that allows for infinite adjustability of the seed meter.
Still another objective of the present invention is the provision of an adjustment mechanism for a seed meter of a precision planting machine which can be quickly and easily adjusted for the desired seed position in a raised bed.
Yet another objective of the present invention is the provision of an adjustment mechanism for a seed meter which allows for quick and easy calibration before the planter is in the field.
Another objective of the present invention is a method of adjusting the drive chain of a seed meter to allow for fine tuning of the seed drop position.
Yet another objective of the present invention is the provision of a seed meter adjustment mechanism which is economical to manufacture and accurate in use.
These and other objectives will become apparent from the following description of the invention.